Highly Stereoselective Synthesis of Tetrasubstituted Acyclic All-Carbon Olefins via Enol Tosylation and Suzuki–Miyaura Coupling
作者:Beryl X. Li、Diane N. Le、Kyle A. Mack、Andrew McClory、Ngiap-Kie Lim、Theresa Cravillion、Scott Savage、Chong Han、David B. Collum、Haiming Zhang、Francis Gosselin
DOI:10.1021/jacs.7b05071
日期:2017.8.9
A highly stereocontrolled synthesis of tetrasubstituted acyclic all-carbon olefins has been developed via a stereoselective enolization and tosylate formation, followed by a palladium-catalyzed Suzuki-Miyaura cross-coupling of the tosylates and pinacol boronic esters in the presence of a Pd(OAc)2/RuPhos catalytic system. Both the enol tosylation and Suzuki-Miyaura coupling reactions tolerate an array
1,2‐Aryl Migration Induced by Amide C−N Bond‐Formation: Reaction of Alkyl Aryl Ketones with Primary Amines Towards α,α‐Diaryl β,γ‐Unsaturated γ‐Lactams
作者:Rong Hu、Yigao Tao、Xiaofeng Zhang、Weiping Su
DOI:10.1002/anie.202014900
日期:2021.4.6
that incorporates an unusual 1,2‐aryl migration induced by amide C−N bond formation to produce a class of structurally novel α,α‐diaryl β,γ‐unsaturated γ‐lactams in generally good‐to‐excellent yields. This cascade reaction has a broad substrate scope with respect to primary amines, allows a wide spectrum of (hetero)aryl groups to smoothly undergo 1,2‐migration, and tolerates electronically diverse
Catalytic Enantioselective Synthesis of Acyclic Quaternary Centers: Palladium-Catalyzed Decarboxylative Allylic Alkylation of Fully Substituted Acyclic Enol Carbonates
作者:Eric J. Alexy、Haiming Zhang、Brian M. Stoltz
DOI:10.1021/jacs.8b05560
日期:2018.8.15
The firstenantioselective palladium-catalyzed decarboxylative allylic alkylation of fully substituted acyclic enol carbonates providing linear α-quaternary ketones is reported. Investigation into the reaction revealed that the use of an electron-deficient phosphinooxazoline ligand renders the enolate geometry of the starting material inconsequential, with the same enantiomer of product obtained in
Rh‐Catalyzed Coupling of Aldehydes with Allylboronates Enables Facile Access to Ketones
作者:Kezhuo Zhang、Jiaxin Huang、Wanxiang Zhao
DOI:10.1002/chem.202103851
日期:2022.3.10
A novel strategy for the preparation of ketones from aldehydes and allylic boronic esters is presented. This reaction involves the allylation of aldehydes with allylic boronic esters and the Rh-catalyzed chain-walking of homoallylic alcohols. This approach features mild reaction conditions, broad substrate scope, and excellent functional groups. Mechanistic studies also supported that a tandem allylation
Lithium Hexamethyldisilazide-Mediated Enolization of Highly Substituted Aryl Ketones: Structural and Mechanistic Basis of the <i>E</i>/<i>Z</i> Selectivities
作者:Kyle A. Mack、Andrew McClory、Haiming Zhang、Francis Gosselin、David B. Collum
DOI:10.1021/jacs.7b05057
日期:2017.9.6
Enolizations of highly substituted acyclic ketones used in the syntheses of tetrasubstituted olefin-based anticancer agents are described. Lithium hexamethyldisilazide (LiHMDS)-mediated enolizations are moderately Z-selective in neat tetrahydrofuran (THF) and E-selective in 2.0 M THF/hexane. The results of NMR spectroscopy show the resulting enolates to be statistically distributed ensembles of E,E-
描述了用于合成基于四取代的烯烃的抗癌剂的高度取代的无环酮的烯醇化。六甲基二硅氮化锂 (LiHMDS) 介导的烯醇化在纯四氢呋喃 (THF) 中具有中等 Z 选择性,在 2.0 M THF/己烷中具有 E 选择性。 NMR 光谱结果表明,所得烯醇化物是 E,E-、E,Z- 和 Z,Z-烯醇化物二聚体的统计分布整体,其亚基反映了选择性。速率研究的结果追踪了 E 和 Z 异构体分别对基于四溶剂化和五溶剂化单体的过渡结构的偏好。使用 LiHMDS 在 N,N-二甲基乙胺或三乙胺的甲苯中进行烯醇化,得到分别含有 E 和 Z 异构体的 LiHMDS-烯醇锂混合二聚体的 65:1 混合物。光谱研究表明,在三烷基胺/甲苯中,酮与 LiHMDS 发生条件依赖性络合。速率数据将高选择性完全归因于基于单溶剂化二聚体的过渡结构。